/*-------------------------------------------------------------------------
 * Filename:      xmodem.c
 * Version:       $Id: xmodem.c,v 1.1 2008/03/17 08:02:32 zhulin Exp $
 * Copyright:     Copyright (C) 2001, Hewlett-Packard Company
 * Author:        Christopher Hoover <ch@hpl.hp.com>
 * Description:   xmodem functionality for uploading of kernels 
 *                and the like
 * Created at:    Thu Dec 20 01:58:08 PST 2001
 *-----------------------------------------------------------------------*/
/*
 * xmodem.c: xmodem functionality for uploading of kernels and 
 *            the like
 *
 * Copyright (C) 2001 Hewlett-Packard Laboratories
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ident "$Id: xmodem.c,v 1.1 2008/03/17 08:02:32 zhulin Exp $"

#include "config.h"
#include "serial.h"
#include "util.h"
#include "crc16.h"

#define SOH 0x01
#define STX 0x02
#define EOT 0x04
#define ACK 0x06
#define NAK 0x15
#define CAN 0x18
#define BS  0x08
#define CTRLZ 0x1A

#define DLY_1S	1000
#define MAXRETRANS	10
/*

Cf:

  http://www.textfiles.com/apple/xmodem
  http://www.phys.washington.edu/~belonis/xmodem/docxmodem.txt
  http://www.phys.washington.edu/~belonis/xmodem/docymodem.txt
  http://www.phys.washington.edu/~belonis/xmodem/modmprot.col

*/

#define TIMEOUT	10 
#define MAXERRORS 10

#define ERROR(...) do { } while (0)


static char blockBuf[1024];

static inline void ReadFlush() {
	SerialInputFlush();
}

unsigned char _inbyte(unsigned int timeout)
{
	char buf[1];
	int n;

	n = SerialInputBlock_msec(buf, 1, timeout);

	if (n == 1)
		return buf[0] & 0xff;
	else
		return -1;
}

void _outbyte(unsigned char ch)
{
		SerialOutputRawByte(ch);
}

static void flushinput(void)
{
	SerialInputFlush();
}
  
int ReadByteWithTimeout(unsigned int timeout) 
{
	char buf[1];
	int n;

	n = SerialInputBlock(buf, 1, timeout);

	if (n == 1)
		return buf[0] & 0xff;
	else
		return -1;
}

#if 0	/* NK9 */
int XModemReceive(char *bufBase, int bufLen)
#else
int XModemReceive(char *bufBase)
#endif
{
	unsigned int errors = 0;
	unsigned int wantBlockNo = 1;
	unsigned int length = 0;
	int crc = 1;
	char nak = 'C';

	ReadFlush();

	/* Ask for CRC; if we get errors, we will go with checksum */
	SerialOutputRawByte(nak);

	for (;;) {
		int blockBegin;
		int blockNo;
		int blockNoOnesCompl;
		int cksum = 0;
		int crcHi = 0;
		int crcLo = 0;
		int blockLength;

		blockBegin = ReadByteWithTimeout( TIMEOUT );
		if (blockBegin < 0)
			goto timeout;

		nak = NAK;

		switch (blockBegin) {
		case SOH:
		case STX:
			break;

		case EOT:
			SerialOutputRawByte(ACK);
			goto done;

		default:
			goto error;
		}

		/* block no */
		blockNo = ReadByteWithTimeout( TIMEOUT );
		if (blockNo < 0)
			goto timeout;

		/* block no one's compliment */
		blockNoOnesCompl = ReadByteWithTimeout( TIMEOUT );
		if (blockNoOnesCompl < 0)
			goto timeout;

		if (blockNo != (255 - blockNoOnesCompl)) {
			SerialOutputString("bad block ones compl\n");
			goto error;
		}

		blockLength = (blockBegin == SOH) ? 128 : 1024;

		{
			int i;

			for (i = 0; i < blockLength; i++) {
				/* simon */
				/* unsigned char cc; */
				int cc;
//				signed char cc;
				cc = ReadByteWithTimeout( TIMEOUT );
				if (cc < 0)
					goto timeout;
				blockBuf[i] = cc;
			}
		}

		if (crc) {
			crcHi = ReadByteWithTimeout( TIMEOUT );
			if (crcHi < 0)
				goto timeout;

			crcLo = ReadByteWithTimeout( TIMEOUT );
			if (crcLo < 0)
				goto timeout;
		} else {
			cksum = ReadByteWithTimeout( TIMEOUT );
			if (cksum < 0)
				goto timeout;
		}

		if (blockNo == ((wantBlockNo - 1) & 0xff)) {
			/* a repeat of the last block is ok, just ignore it. */
			/* this also ignores the initial block 0 which is */
			/* meta data. */
			goto next;
		} else if (blockNo != (wantBlockNo & 0xff)) {
			SerialOutputString("unexpected block no, ");
			SerialOutputHex(blockNo); SerialOutputString(", expecting ");
			SerialOutputHex(wantBlockNo); SerialOutputByte('\n');
			goto error;
		}

		if (crc) {
			int crc = 0;
			int i, j;
			int expectedCrcHi;
			int expectedCrcLo;

			for (i = 0; i < blockLength; i++) {
				crc = crc ^ (int) blockBuf[i] << 8;
				for (j = 0; j < 8; j++)
					if (crc & 0x8000)
						crc = crc << 1 ^ 0x1021;
					else
						crc = crc << 1;
			}

			expectedCrcHi = (crc >> 8) & 0xff;
			expectedCrcLo = crc & 0xff;

			if ((crcHi != expectedCrcHi) ||
			    (crcLo != expectedCrcLo)) {
				SerialOutputString("crc error, expected ");
				SerialOutputHex(expectedCrcHi); SerialOutputByte(' ');
			       	SerialOutputHex(expectedCrcLo); SerialOutputString(", got ");
				SerialOutputHex(crcHi); SerialOutputHex(crcLo); SerialOutputByte('\n');
				goto error;
			}
		} else {
			unsigned char expectedCksum = 0;
			int i;

			for (i = 0; i < blockLength; i++)
				expectedCksum += blockBuf[i];

			if (cksum != expectedCksum) {
				SerialOutputString("checksum error, expected ");
				SerialOutputHex(expectedCksum);  SerialOutputString(", got ");
				SerialOutputHex(cksum); SerialOutputByte('\n');
				goto error;
			}
		}

		wantBlockNo++;
		length += blockLength;

#if 0
		if (length > bufLen) {
			SerialOutputString("out of space\n");
			goto error;
		}
#endif

		{
			int i;
			for (i = 0; i < blockLength; i++)
				*bufBase++ = blockBuf[i];
		}

	next:
		errors = 0;
		SerialOutputRawByte(ACK);
		continue;

	error:
	timeout:
		errors++;
		if (errors == MAXERRORS) {
			/* Abort */
			int i;

			// if using crc, try again w/o crc
			if (nak == 'C') {
				nak = NAK;
				errors = 0;
				crc = 0;
				goto timeout;
			}

			SerialOutputString("too many errors; giving up\n");
			for (i = 0; i < 5; i ++)
				SerialOutputRawByte(CAN);
			for (i = 0; i < 5; i ++)
				SerialOutputRawByte(BS);
			return -1;
		}

		ReadFlush();
		SerialOutputRawByte(nak);
	}

 done:
	return length;
}


int xmodemTransmit(unsigned char *src, int srcsz)
{
	unsigned char xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */
	int bufsz, crc = -1;
	unsigned char packetno = 1;
	int i, c, len = 0;
	int retry;

	for(;;) {
		for( retry = 0; retry < 16; ++retry) {
			if ((c = _inbyte((DLY_1S)<<1)) >= 0) {
				switch (c) {
				case 'C':
					crc = 1;
					goto start_trans;
				case NAK:
					crc = 0;
					goto start_trans;
				case CAN:
					if ((c = _inbyte(DLY_1S)) == CAN) {
						_outbyte(ACK);
						flushinput();
						return -1; /* canceled by remote */
					}
					break;
				default:
					break;
				}
			}
		}
		_outbyte(CAN);
		_outbyte(CAN);
		_outbyte(CAN);
		flushinput();
		return -2; /* no sync */

		for(;;) {
start_trans:
			xbuff[0] = SOH; bufsz = 128;
			xbuff[1] = packetno;
			xbuff[2] = ~packetno;
			c = srcsz - len;
			if (c > bufsz) c = bufsz;
			if (c >= 0) {
#if 0
				memset (&xbuff[3], 0, bufsz);
#else
				MyMemSetChar(&xbuff[3], 0, bufsz);
#endif
				if (c == 0) {
					xbuff[3] = CTRLZ;
				}
				else {
#if 0
					memcpy (&xbuff[3], &src[len], c);
#else
					MyMemCpyChar(&xbuff[3], &src[len], c);
#endif
					if (c < bufsz) xbuff[3+c] = CTRLZ;
				}
				if (crc) {
					unsigned short ccrc = crc16_ccitt(&xbuff[3], bufsz);
					xbuff[bufsz+3] = (ccrc>>8) & 0xFF;
					xbuff[bufsz+4] = ccrc & 0xFF;
				}
				else {
					unsigned char ccks = 0;
					for (i = 3; i < bufsz+3; ++i) {
						ccks += xbuff[i];
					}
					xbuff[bufsz+3] = ccks;
				}
				for (retry = 0; retry < MAXRETRANS; ++retry) {
					for (i = 0; i < bufsz+4+(crc?1:0); ++i) {
						_outbyte(xbuff[i]);
					}
					if ((c = _inbyte(DLY_1S)) >= 0 ) {
						switch (c) {
						case ACK:
							++packetno;
							len += bufsz;
							goto start_trans;
						case CAN:
							if ((c = _inbyte(DLY_1S)) == CAN) {
								_outbyte(ACK);
								flushinput();
								return -1; /* canceled by remote */
							}
							break;
						case NAK:
						default:
							break;
						}
					}
				}
				_outbyte(CAN);
				_outbyte(CAN);
				_outbyte(CAN);
				flushinput();
				return -4; /* xmit error */
			}
			else {
				for (retry = 0; retry < 10; ++retry) {
					_outbyte(EOT);
					if ((c = _inbyte((DLY_1S)<<1)) == ACK) break;
				}
				flushinput();
				return (c == ACK)?len:-5;
			}
		}
	}
}
